Granular blast in the bone marrow of a dog with AML

Granular blast

A bone marrow aspirate from a dog with acute monoblastic leukemia had >80% blasts. Some blasts had moderate numbers of chunky purple (“mast cell-like”) granules (arrow), a feature we have seen in dogs with AML, particularly with monocytic differentiation. These are thought to be a version of a granular blast (Wright’s stain, 100x objective).